On Jun 6, 2019, at 1:48 PM, Brian Goetz <brian.go...@oracle.com> wrote: > … > But, I’m not particularly compelled by this — I think the strategy we took > for enums is mostly good enough. So I’m voting for pure B.
Yes, I track with your reasoning. Pure B is perfectly fine as wherever there is a mandated translation strategy to inform the user where (in the reflective APIs) to look for the annotation. You can achieve A-like effects with appropriate conventions. For example, if I have a little library of annotations just for record components, I can target them to fields, and look for them in Class.getDeclaredFields, even if the fields happen to be private. (Right?) I'd kind of like to call this B+-. No new channels or API points, but a known way to find component annotations, by looking at the fields. If we wanted to make things more explicit, we could incrementally modify a plan B with A-like conventions to a plan B+ in which there's a new annotation target for components, but it still gets passed through the field channels. This wouldn't require new API points or classfile formats. Strictly speaking a new annotation target isn't required either, just some marker or other; another meta-annotation, but not a target type. The net of the above is B seems sufficient, although it also seems necessary to specify a deterministic place to find component annotations per se (fields, I suppose). And if we want to do more it's easy to add a bit meta-data with a meta-annotation, not necessarily a target type.
